Yellow Nuka-Cola is a "variation" of regular Nuka-Cola, both yellow in color and with an "interesting" smell. In Chicago, during the Brotherhood of Steel's reign, there were reports of this strange yellow Nuka-Cola. However, it was quickly identified as a substance designed by a "mad naked man" who "made water." Considering this, and the fact that it's poisonous to anyone naive enough to actually drink it, it is apparent that the so-called cola is in fact a generous helping of urine.